Daily deals make e-books instant bestsellers

Mr Grandinetti said one book, 1,000 Recordings to Hear Before You Die,was selling, on average, less than one e-book a day on Amazon. After it was listed as a Kindle Daily Deal last year, it sold 10,000 copies in less than 24 hours.

HUGE SALES INCREASESome titles have tripled that number: on a single day in December, nearly 30,000 people snapped up digital copies of Under the Dome, by Stephen King, a novel originally published in 2009 by Scribner. For publishers and authors, having a book chosen by a retailer as a daily deal can be like winning the lottery, an instant windfall of sales and exposure.

In February, a crime novel by the little-known author Lorena McCourtney, released by the Christian publishing imprint Revell, was selected as a Nook Daily Find. The sales from that promotion alone were enough to propel it onto The New York Times best-seller list.

At HarperCollins, executives said they have seen books designated as daily deals go from 11 copies sold in one day, to 11,000 copies the next.

Not all of them take off, though. One publisher said some books fizzle out quickly, attracting only several hundred downloads in a day. Another publisher said he is hesitant to discount that steeply, fearing that consumers will eventually resist paying more than a few dollars for a book.

But part of the allure of flash sales is what can happen afterward: a ripple effect that increases sales on an author's other works.

INSPIRING FURTHER SALESIf one book in a series is offered in a one-day promotion, readers who liked it will often buy others in the series.

"We've found that one of the key opportunities with it is the halo effect," said David Steinberger, the chief executive of Perseus Books Group. "It's hard for it to be highly successful economically at these very low prices, even if the volume goes up for a single day. But if you create awareness for the book, it can make a lot of sense for the author."

The book that is discounted often sells at a higher level after the daily deal than it did before, even though it has returned to the regular price.

Food Inc., the companion book to the documentary film, sold hundreds of copies each month before a one-day promotion on Amazon. On the day of the promotion, it sold thousands of copies; afterwards, the book sold steadily at twice the level before the promotion, Mr. Steinberger said.

Tim Lavalli, a writer in Berkeley, California, said he reads at least two books a week, receiving almost all his recommendations from BookBub or Ereader News Today, another daily-deal aggregator.